Public Bath No.7 Nanakuri-no-yu

Day Use

Yes

06:00–22:00

with a key when staying at the ryokan

¥0

with a key when staying at the ryokan

Bathing & Water

Natural onsen water

Uses natural hot spring water

Outdoor BathNo

Open-air outdoor bath

Indoor BathYes

Enclosed indoor bathing area

SaunaNo

Sauna room of any kind

Cold BathNo

Cold water plunge bath, typically used after sauna

Bathing Arrangements

Private BathNo

A private bath you can reserve for yourself or your group

Mixed BathingNo

Shared bathing area for all genders

Policies & Services

WashingNo

Shower, wash stations, soap and shampoo provided

七操の湯

Nanakuri-no-yu Spring

Operated by · 横湯組

硫

Sulfate

+ Chloride

Color: almost colorless and clear
Taste: slightly salty
Odor: odorless

Sodium-Calcium Sulfate-Chloride spring

pH 7.3NeutralHot source · 51°CHigh silica

Composition fingerprint1.4 g/kg dissolved · Hypotonic

Na⁺58

Ca²⁺37

SO₄²⁻50

Cl⁻47

◀ CationsAnions ▶

Sodium Na⁺: salt's cation — pairs with chloride to make the water salty.
Sulfate SO₄²⁻: "gypsum / Glauber's salt" — vessels and wound healing.

Known good for

Aches & jointsstiff shoulders
Circulationtired legs
Warmingcold sensitivity

Nanakuri-no-yu rises in the Yokoyu quarter of Yamanouchi, Nagano, as a sodium-calcium sulfate-chloride spring — sulfate leads the anions with a chloride edge behind it. The water is neutral and hypotonic, moderately mineralized at about 1.4 g/kg of dissolved solids: almost colorless and clear, odorless, with a faint salt tang on the lips. What lifts it above an ordinary sulfate bath is metasilicic acid at 153.8 mg/kg, enough silica to leave a thin moisturizing film and place the water squarely in Japan's beauty-water family. Worth knowing that the certificate was sampled at the bath inlet of the No.7 public bath rather than at the wellhead, so these figures describe the water as it actually reaches the tub.

Sampled at bath inlet·Analyzed Jun 10, 2016·一般社団法人上田薬剤師会検査センター·Cert no. 中28-4（No.429）

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